It is known to form field programmable integrated circuit memory matrixes with a variety of different electrically alterable elements. Thus for example, fusible links and transistors are employed for this purpose. The fusible link matrix normally incorporates a link of nichrome or the like which melts and separates upon the application of sufficient electrical power thereto to form an open circuit as the programmed bit in the matrix. A transistor matrix is programmed by application of sufficient electrical power to electrically short one junction of the transistor so as to leave only a single forward conducting diode as a programmed bit in the matrix. These type of matrixes have generally replaced the diode matrixes and are herein termed ROMs.
The advantages and wide applicability of field programmable memories has been amply demonstrated by the commercial success thereof. In this rapidly moving field there have been made numerous significant advancements including the programming method and system of U.S. Pat. No. 3,733,690. As a continuation of this rapid advancement in the field, the present invention provides an improved programmable ROM element and matrix affording greater flexibility to the designer and simplification of programming requirements.